Alert archive / Wyoming / Severe Thunderstorm Watches in 2024
Severe Thunderstorm Watch 430
The Storm Prediction Center issued this severe thunderstorm watch at Jun 17, 2024, 4:32 PM MDT for 4 counties in Montana; 6 counties in Wyoming. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 17, 2024, 4:32 PM MDT (22:32 UTC)
- Expired
- Jun 17, 2024, 9:31 PM MDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties Carter County, MT, Custer County, MT, Fallon County, MT, Powder River County, MT, Campbell County, WY, Converse County, WY, Crook County, WY, Johnson County, WY, Niobrara County, WY, Weston County, WY
The radar
The Rapid City radar (KUDX), 209 km from the middle of the area, began a volume at 22:32 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 5%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 50%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
2 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 17, 4:36 PM MDT | Severe Thunderstorm Warning | BYZ | Custer, Powder River | 39 min |
| Jun 17, 6:58 PM MDT | Severe Thunderstorm Warning | UNR | Crook | 62 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Rapid City, SD (KUNR), launched 12:00Z, 10.5 hours before the alert went out and 206 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2056 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 2 m²/s²
- 0-3 km storm-relative helicity
- 123 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
914
WWUS20 KWNS 172230
SEL0
SPC WW 172230
MTZ000-WYZ000-180500-
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 430
NWS Storm Prediction Center Norman OK
430 PM MDT Mon Jun 17 2024
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Southeastern Montana
East-central and northeastern Wyoming
* Effective this Monday afternoon and evening from 430 PM until
1100 PM MDT.
* Primary threats include...
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
Isolated damaging wind gusts to 70 mph possible
SUMMARY...Thunderstorms should continue to develop on the east side
of higher terrain around the Bighorns and northern Laramie Range,
and move northward to northeastward. Activity should cross a narrow
corridor of favorable instability and shear for large hail and
severe gusts to result, before weakening closer to the Dakotas
border.
The severe thunderstorm watch area is approximately along and 50
statute miles east and west of a line from 110 miles south of
Gillette WY to 30 miles west northwest of Baker MT. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU0).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 429...
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
21030.
...EdwardsSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 17, 2:45 PM MDT | Mesoscale Discussion | SPC | Carter, Powder River | 90 min |
| Jun 17, 5:55 PM MDT | Mesoscale Discussion | SPC | Carter, Powder River | 95 min |
| Jun 16, 7:38 PM MDT | Mesoscale Discussion | SPC | Goshen | 2 hr |
Nearby
Severe Thunderstorm Watches in Wyoming, 2024Severe Thunderstorm Watches in Montana, 2024Every severe thunderstorm watch in 2024
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.